The invention relates to a method and an apparatus for filling containers with piece goods.
For packaging systems, it is known to put piece goods, which are delivered to a packaging station via feed conveyors, into containers by means of robots. EP-A-0 250 470 discloses robots of this type, also referred to as pickers, which are suitable for use in packaging lines. What is concerned here is a robot arm with a base element, to which an operating part is attached via three two-part arms and on which in turn grippers or suction elements are arranged.
Primarily when the piece goods are supplied with irregular spacing and unordered, optical detection systems are used in order to register the position and alignment of the individual piece goods on the feed conveyor, as disclosed in U.S. Pat. No. 5,186,599, for example. This data is transmitted to a robot control system, which controls the individual robots appropriately in order to put as many of the piece goods as possible into the container. In the process, the first robot in the conveying direction will grip as many piece goods as possible and the following robots will attempt to remove the remainder from the feed conveyor.
However, this leads to the individual robots being utilized to different extents. The first robot in the conveying direction has a higher operating loading than the last in the series. In addition, all the robots are subjected to wide output fluctuations, as can be seen from FIG. 1. This illustrates the number of products which are gripped per second by a robot. These values are indicated for a total of four robots, the individual robots being numbered in the conveying direction. This means that robot number 1 is the first robot in the conveying direction. As can be seen in FIG. 1, the first two robots always operate at their maximum output limit. The third robot frequently reaches its output limit, but also exhibits wide fluctuations in the operating loading. The fourth robot, by contrast, is hardly utilized, but is subject to massive output fluctuations.
This distribution of the operating loading has the disadvantage that robots which always operate at their output limit or which are subjected to wide fluctuation have a shortened lifetime because of the high mechanical stress.
It is therefore an object of the invention to specify a method and an apparatus which increases the lifetime of the individual robots.
This object is achieved by a method and an apparatus having the features of patent claim 1 and 7, respectively.
According to the invention, the robots are driven in such a way that all the robots are utilized as uniformly as possible over time and are not subjected to any wide output fluctuations. This leads to all the robots being in at least approximately the same output range, the output range lying underneath a maximum output range. In a preferred variant of the method, not only are the robots driven appropriately, but the speed of the container conveyer is also controlled.
Further advantageous embodiments emerge from the dependent patent claims.